This invention relates to drilling rigs, and in particular to a swing-out apparatus which includes a casing hammer that can be displaced from an active, deployed position to an inactive position.
Under normal drilling conditions for water wells, when the drilled hole is completed, the drill rod must be removed. This is typically accomplished with either a top head drive or a main winch extending from the mast of the drill rig. Typically, the main winch is much faster for withdrawing the drill rod. To use the winch, what is known as the casing hammer, which is typically deployed at a position above the well casing, is moved out of the way. In the past, this has been done by removing guides that physically attach the hammer to the mast, and then the hammer is placed aside. Another way has been to use a sled on the drilling mast, and attach the casing hammer to the sled on a pair of hinges. The hammer can then be swung out of the way while still attached to the sled and the drill rig so that other work can be performed.
While swinging the hammer out of the way, while maintaining it on the drill rig, is advantageous, in the past, that has been done by hand. This is very difficult, as the casing hammer is quite heavy, and therefore difficult to either move into place above the well casing for the drilling process, or move aside so that the casing and well head is clear for easy access.